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Q: What is the "dark side" of the moon?
A: Short answer? That's wrong. An audio error! But wrong. Assuming they do not talk about the Pink Floyd album or the French "mockumentary", people who say that the "dark side of the moon" almost always relates to the moon far away a side that, although it permanently shows away from those of us, the planets, actually sees how much sunlight is like the side of the Earth.
Maybe he already knew that. But! Did you also know that the sliders on the distant far side of the Moon are constantly slipping in view? Or that certain lunar regions are actually shrouded in permanent darkness?
To understand why, you first need to understand why one side of the moon is forever highlighted by the Earth. To those of us here on the ground, the natural satellite on our planet never turns. But it actually turns around all the time – it only spins on its axis and changes it around our planet at the same rate: once every 27 days or so. When the cosmic body revolves around its parent and its axis at the same rate, astronomers say it is "sufficiently locked".
Our moon was not born this way. Astronomers think that, like many other natural satellites, he began his life at a very different rate. (In the case of our moon, astronomers think that it once developed more rapidly around its axis.) But over time, the gravity of our planet was the torque of the projection on the surface of the moon, forcing its rotation to synchronize with its orbital period. This phenomenon is, in fact, quite honorable: Many of the moons of Saturn and Jupiter are snap-locked with their native planet.
The locking lock is why we did not have a clue that came to the far side of the Moon until 1959, when the Soviet space probe Luna 3 bought the first pictures of the landscape that the crater carried. Since then, we have received some good views: In 1968, the astronauts in the NASA mission "Apollo 8" became the first people to see on the far side of the Moon with their own eyes. NASA's lunar spinning orbit maps all of the high-resolution moon surface from 2009. And in the first few days of 2019, China became the first country to make a soft landing of the spacecraft and deploy a rover to the eternally hidden face of the moon. China's Chang 4 eagle and Jade Rabbit 2 rover will give humanity the first close look at that remote lunar landscape.
But the truth is: You do not need spacecraft to see it further from the moon. While you can only see a maximum of 50 percent of the Moon's disk at any given time, bonus hits on its surface are constantly revealed to careful observers. In fact, during the lunar cycle, up to 59 percent of the Moon's surface becomes visible to heaven on Earth-assuming they know what to look for.
Check out these images from the NASA visualization study. It was done using satellite images captured by the agency Luna Scout Orbiter. Phase changes are no doubt familiar with this: Because the position of the Moon changes with respect to the Sun and Earth, darkness is rounded up and withdraws from the person who is locked locked with our planet (as it retracts and engages the pulling person). But this animation – which condenses two and a half lunar cycles into a single 13-second gif – illustrates something about the moon you might not have noticed before: The moon is … mud.
Astronomers call these valves, and they are caused by the orientation of the axis of the moon and the elliptical form of the orbit. The inclination of its axis relative to the Earth makes the moon appear to transmit the planet a slow and gentle movement, allowing observers to follow their northern and southern pillars. Also, the eccentricity of the orbit of the moon gives the person a small hat, allowing those of us on Earth to perform above its eastern and western edges, as they move back and forth, not unlike the party parrot: in Slack. (Its irregular orbit also explains the apparent changes in the moon in size, due to a different distance from the Earth.)
And the inclination of the axis of the moon produces another interesting phenomenon: patches on the surface of the moon that are really, really, constantly dark:
The picture above is a map for illuminating the southern pole of the moon. It is a complex image built by more than 1,700 photographs captured by the lunar Scout Orbiter for a period of six months. The regions of the pillar that did not see the light at that time appear black; those who have seen a continuous light appear white; Gray regions saw something between them. As a reference point, the black circle near the center of the image is Shackleton Crater, blow a crater 13 miles across with a rim that throws a long, eternal shadow on its interior.
All this is to say: "The Dark Side of the Moon" may not technically exist, but "craters of eternal darkness" – which sound even cooler – are definitely doing.
Robbie Gonzalez is an older writer for the WIRED's Science Desk. His fascination with the moon dates back to his childhood when, at the age of four, he first saw it through a telescope. (He still owns that telescope.)
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